Problem Statement: While rates of lifetime forced sexual intercourse have increased in Kentucky over the past five years among high school students, Kentucky is working to reduce this trend. Through CDC assistance, Kentucky Association of Sexual Assault Programs, Inc. (KASAP) is ready to implement the Green Dot bystander intervention program for primary prevention of sexual violence (SV). Importance: We now have the unique and time-sensitive opportunity to evaluate a statewide bystander intervention which will be implemented by KASAP Educators across Kentucky through high schools beginning in 2010. Green Dot empowers students to actively question peer support for SV and become change agents who can play a significant role in ending SV. Innovation: While several bystander intervention programs have been implemented, few been empirically evaluated and none have been evaluated on a statewide basis using the same intervention protocol. Purpose: To evaluate the statewide application of Green Dot among high schools students. We hypothesize that students in high schools with Green Dot will over time report lower rates of SV compared with students in comparable high schools randomized not to have Green Dot. This reduction in SV will be mediated through a reduction in social norms supporting SV and an increase in bystander behaviors. Specific Aims: To prospectively determine whether relative to students in high schools without Green Dot, those in schools with Green Dot (Aim 1) report lower rates of SV, (Aim 2) a greater frequency of bystander behaviors, and (Aim 3) fewer social norms supporting SV. Finally because Green Dots draws on social diffusion of innovation theory we propose (Aim 4) to determine how Green Dot influences bystander behaviors in the first and second order social networks of students who do and do not receive Green Dot training. Methods: A population-based controlled intervention trial will be used to test the efficacy of Green Dot. Both panel and web-based cohort survey methods will be used to provide baseline and prospective data on student's attitudes supporting SV, bystander behaviors and SV experiences. Setting: In each of the 13 KASAP regions, 2 demographically comparable high schools with at least 200 students per grade will be recruited to participate in Green Dot either as the intervention or control site. Schools will be randomly assigned to the intervention. Study Population: All students in participating high schools will be invited to complete anonymous panel surveys beginning spring 2010 through 2014; we anticipate that 6500 students in Green Dot and 6500 in control schools will complete surveys each year. We estimate that 650 students receiving Green Dot training and 650 students not so trained will complete the web-surveys, (2011-2014). External sources of data to document SV will be obtained from high schools. Implications for Prevention: This state-wide, population-based, multi-site controlled intervention trial will provide an empirical test of a promising intervention, which, if proven effective, could result in the primary prevention of SV and a reduction in the health and academic consequences of SV.